CREATE TABLE world.city (

ID int NOT NULL AUTO_INCREMENT,

Name char(35) NOT NULL DEFAULT '',

CountryCode char(3) NOT NULL DEFAULT '',

District char(20) NOT NULL DEFAULT '',

Population int NOT NULL DEFAULT '0',

PRIMARY KEY (ID),

KEY (CountryCode)

) ENGINE=InnoDB;

You want to improve the performance of this query:

SELECT Name

FROM world.city

WHERE Population BETWEEN 100000 AND 200000;

Which change enables the query to succeed while accessing fewer rows?

A user accidentally updated some data on the slave.

To fix this you stopped replication and successfully reverted the accidental changes.

Examine the current GTID information:

Master uuid: aaaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa

Master gtid_executed: aaaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-10300

Master gtid_purged: aaaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-3820

Slave uuid: bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb

Slave gtid_executed: bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb:1-10167,

aaaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-2312

Slave gtid_purged: aaaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa:1-9

You must fix GTID sets on the slave to avoid replicating unwanted transactions in case of failover.

Which set of actions would allow the slave to continue replicating without erroneous transactions?

The database size is static and including indexes is 19G.

Total system memory is 32G.

After profiling the system, you highlight these MySQL status and global variables:

（含图）

The OS metrics indicate that disk is a bottleneck.

Other variables retain their default values.

Which three changes will provide the most benefit to the instance? (Choose three.)

mysql> SHOW SLAVE STATUS\G

*************************** 1. row ***************************

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

Seconds_Behind_Master: 1612

Seconds_Behind_Master value is steadily growing.

What are two possible causes? (Choose two.)

CREATE ROLE r_world_rd;

GRANT SELECT ON world.* TO r_world_rd;

CREATE USER john IDENTIFIED BY 'P@ssword';

GRANT r_world_rd TO john;

Examine these grants issued by user John:

mysql> SHOW GRANTS;

+--------------------------------------------+

| Grants for john@%                                            |

+--------------------------------------------+

| GRANT USAGE ON *.* TO `john`@`%`           |

| GRANT `r_world_rd`@`%` TO `john`@`%`  |

+--------------------------------------------+

2 rows in set (0.01 sec)

mysql> SELECT * FROM world.city;

ERROR 1142 (42000): SELECT command denied to user 'john'@'localhost' for table 'city'

What is the reason for the error?

Which command will do this?

dba.rebootClusterFromCompleteOutage()

Which two statements are true? (Choose two.)